Comment by agersant

For the simplest use cases, I can plug Polaris[1] which I have been maintaining for many years.

Pros:

  - Very reliable
  - Very performant
  - Works well with large collections
  - Trivial setup
  - FOSS

Cons:

  - Small featureset
  - Infrequent updates
  - No official iOS client (there is a third party client however)

[1]: https://github.com/agersant/polaris